Microbiology Chapter 2

Brightfield

A microscope that uses multiple lenses is called a __________________ microscope.

Fluorochromes

Chromophores that absorb and then emit light are called_____________.

Light is refracted toward a focal point-A prism can separate the colors of white light (dispersion) because different frequencies of light have different refractive indices for a given material.

Explain how a prism separates white light into different colors.

Perform an acid fast stain

How could you identify whether a particular bacterial sample contained specimens with mycolic acid rich cell walls?

Atomic force

In a(n) ___________ microscope, a probe located just about the specimen moves up and down in response to forces between atoms and the tip of the probe.

1)eye piece 2)revolving nose piece 3)objective lenses 4)stage 5)condenser 6)illuminator 7)mechanical stage 8)coarse 9)fine focus 10)reheostat (light intensity)

Name ten components of the brightfield microscope

Gram stain

The_________ is used to differentiate bacterial cells based on the components of their cell walls.

B.only the SEM specimen requires a sputter coating

What is one difference between specimen preparation for a transmission electron microscope(TEM) and preparation for a scanning electron microscope(SEM)? A.only the TEM specimen requires sputter coating B.ony the SEM specimen requires a sputter coating C.only the TEM specimen must be dehydrated D.only the SEM specimen must be dehydrated

Contains series of lenses that focus light onto speciman

What is the function of the condenser in a brightfield microscope?

400 total magnification

What is the totally magnification of a specimen that is being viewed with a standard ocular lens and a 40x objective lens?

Iodine

What mordant is used in Gram staining?

C.brightfield microscope

What type of microscope uses a cone of light so that light hits the specimen indirectly, producing a darker image on a brighter background? A.transmission electron microscope B.scanning electron microscope C.a brightfield microscope D.a darkfield microscope E.phase-contrast microscope

E.phase-contrast microscope

What type of microscope uses an annular stop? A.transmission microscope B.scanning electron microscope C.brightfield microscope D.darkfield microscope E.phase-contrast microscope

The coarse focus is for larger scale movements while the fine focus is for smaller scale movements-- so it's important to focus larger picture before trying to focus the smaller picture

When focusing a light microscope, why is it best to adjust the focus using the coarse focusing knob before using the fine focusing knob?

Refraction

When you see light bend as it moves from air into water, you are observing________________.

C. Light with a short wavelength

Which of the following has the highest energy? A. Light with a long wavelength B. Light with an intermediate wavelength C. light with a short wavelength D. It is impossible to tell from the information given

D. Infrared rays

Which of the following has the lowest energy? A.visible light B.X-rays C.ultraviolet rays D.infrared rays

D.a confocal scanning laser microscope

Which type of microscope is especially useful for viewing thick structures such as biofilms? A.a transmission electron microscope B.a scanning electron microscope C.a phase-contrast microscope D.a confocal scanning laser microscope E.an atomic scanning laser microscope

B.a scanning electron microscope

Which type of microscope would be the best choice for viewing very small surface structures of a cell? A.a transmission electron microscope B.a scanning electron microscope C.a brightfield microscope D.a darkfield microscope E.a phase-contrast microscope

C.a darkfield microscope

Which would be the best choice for viewing internal structures of a living protist such as a Paramecium? A.a brightfield microscope with a stain B.a brightfield microscope without a stain C.a dark field microscope D.a transmission electron microscope

B. Zaccharias Janssen

Who is the probably inventor of the compound microscope? A. Girolamo Fracastoro B. Zaccharias Janssen C. Antonie van Leeuwenhoek D. Robert Hooke

D. Robert Hooke

Who was the first to describe "cells" in a dead cork tissue? A. Hans Janssen B. Zaccharias Janssen C. Antonie van Leeuwenhoek D. Robert Hooke

They were dead & filled w/air, only rigid cell walls provided structure

Why did the cork cells observed by Robert Hooke appear to be empty, as opposed to being full of other structures?

Janssen was secretive and never published Leeuwenhoek submitted letters in detail of observations to Royal Society

Why is Antonie van Leeuwenhoek's work much better known than that of Zaccharias Janssen?

Two factors are wavelength( short wavelengths need electron microscopes and long wavelengths can use light microscopes) and numerical aperture (lens's ability to gather light- increase numerical aperture=better resolution). If you increase contrast you'll be able to detect different structures easier in specimens For oil immersion lens make sure the oil bridge is still there

You need to identify structures within a cell using a microscope. However, the image appears very blurry even though you have a high magnification. What are some things that you could try to improve the resolution of the image? Describe the most basic factors that affect resolution when you first put the slide onto the stage: then consider more specific factors that could affect resolution for 40x and 100x lenses.

A.fluorescent

You place a specimen under the microscope and notice that parts of the specimen begin to emit light immediately. These materials can be described as____________. A.fluorescent B.phosphorescent C.transparent D.opaque

Red/pink (g-)

You use Gram staining procedure to staying an L-form bacterium(a bacterium that lacks a cell wall). What color will the bacterium be after the staining procedure is finished?

Acid fast

Ziechl-Neelsen staining, a type of__________ staining, is diagnostic for Mycobacterium tuberculosis